/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.google.android.apps.iosched.io;

import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
import static org.xmlpull.v1.XmlPullParser.END_TAG;
import static org.xmlpull.v1.XmlPullParser.START_TAG;
import static org.xmlpull.v1.XmlPullParser.TEXT;

import de.google.android.apps.iosched.provider.ScheduleContract;
import de.google.android.apps.iosched.provider.ScheduleContract.Blocks;
import de.google.android.apps.iosched.util.Lists;
import de.google.android.apps.iosched.util.ParserUtils;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProviderOperation;
import android.content.ContentResolver;

import java.io.IOException;
import java.util.ArrayList;

public class LocalBlocksHandler extends XmlHandler
{
	public LocalBlocksHandler()
	{
		super(ScheduleContract.CONTENT_AUTHORITY);
	}

	@Override
	public ArrayList<ContentProviderOperation> parse(XmlPullParser parser, ContentResolver resolver)
			throws XmlPullParserException, IOException
	{
		final ArrayList<ContentProviderOperation> batch = Lists.newArrayList();
		// Clear any existing static blocks, as they may have been updated.
		final String selection = Blocks.BLOCK_TYPE + "=? OR " + Blocks.BLOCK_TYPE + "=?";
		final String[] selectionArgs =
		{ ParserUtils.BLOCK_TYPE_FOOD, ParserUtils.BLOCK_TYPE_OFFICE_HOURS };
		batch.add(ContentProviderOperation.newDelete(Blocks.CONTENT_URI).withSelection(selection, selectionArgs)
				.build());

		int type;
		
		while ((type = parser.next()) != END_DOCUMENT)
		{
			if (type == START_TAG && Tags.BLOCK.equals(parser.getName()))
			{
				batch.add(parseBlock(parser));
			}
		}

		return batch;
	}

	private static ContentProviderOperation parseBlock(XmlPullParser parser) throws XmlPullParserException, IOException
	{
		final int depth = parser.getDepth();
		final ContentProviderOperation.Builder builder = ContentProviderOperation.newInsert(Blocks.CONTENT_URI);

		String title = null;
		long startTime = -1;
		long endTime = -1;
		String blockType = null;
		String tag = null;
		int type;
		
		while (((type = parser.next()) != END_TAG || parser.getDepth() > depth) && type != END_DOCUMENT)
		{
			if (type == START_TAG)
			{
				tag = parser.getName();
			}
			else if (type == END_TAG)
			{
				tag = null;
			}
			else if (type == TEXT)
			{
				final String text = parser.getText();
				
				if (Tags.TITLE.equals(tag))
				{
					title = text;
				}
				else if (Tags.START.equals(tag))
				{
					startTime = ParserUtils.parseTime(text);
				}
				else if (Tags.END.equals(tag))
				{
					endTime = ParserUtils.parseTime(text);
				}
				else if (Tags.TYPE.equals(tag))
				{
					blockType = text;
				}
			}
		}

		final String blockId = Blocks.generateBlockId(startTime, endTime);

		builder.withValue(Blocks.BLOCK_ID, blockId);
		builder.withValue(Blocks.BLOCK_TITLE, title);
		builder.withValue(Blocks.BLOCK_START, startTime);
		builder.withValue(Blocks.BLOCK_END, endTime);
		builder.withValue(Blocks.BLOCK_TYPE, blockType);

		return builder.build();
	}

	interface Tags
	{
		String BLOCK = "block";
		String TITLE = "title";
		String START = "start";
		String END = "end";
		String TYPE = "type";
	}
}
